What is the difference between map and unordered_map in C++?

Can you explain the difference between map and unordered_map in C++?

Sure! In C++, a map is an ordered associative container that stores elements in key-value pairs, where keys are unique and sorted. An unordered_map, on the other hand, is an unordered associative container that also stores key-value pairs but does not maintain any order.

What are the performance differences between them?

The performance difference lies in their underlying data structures. map is typically implemented as a balanced tree, providing O(log n) time complexity for insertions, deletions, and lookups. unordered_map uses a hash table, offering average O(1) time complexity for these operations, making it generally faster for large datasets.

When should I use one over the other?

Use map when you need to maintain order or require sorted keys. Opt for unordered_map when you prioritize performance and don't need order, especially for large datasets.

Are there any specific use cases for each?

Yes! Use map for scenarios like implementing a priority queue or when you need to iterate in sorted order. Use unordered_map for fast lookups, such as caching or counting occurrences of elements.